1. Field of the Invention
The present invention relates to a liquid crystal display with a plurality of openings (slits) formed on an electrode.
2. Description of the Background Art
As an information display device, a display device with extremely low display brightness of the background display area or the dark display area is demanded, and a vertical alignment liquid crystal display is known as a display device capable of realizing the same. A vertical alignment liquid crystal display is able to achieve extremely low transmissivity in the initial oriented state since the optical characteristics during the frontal viewing in the initial oriented state are approximately equal to the optical characteristics of crossed nicol polarizers.
When liquid crystal molecules of a liquid crystal layer are oriented unidirectionally in a vertical alignment liquid crystal display; that is, when mono-domain alignment is adopted, there is an optimal viewing direction capable of obtaining the optimal contrast in which the bright display state can be viewed the brightest depending on the viewer's viewing direction when voltage is applied to the liquid crystal layer to achieve a bright display state. Moreover, there is also an anti-viewing direction in which the bright display state becomes equal to or less than the transmissivity in the non-voltage-applied area (background area) or the dark display; that is, a direction where display inversion is observed. With this kind of display state, it may become a display state that is completely different from the display state that is recognized during frontal viewing, or the display itself may become a state that is unrecognizable from its appearance.
Meanwhile, in order to obtain favorable viewing-angle characteristics even during voltage application, it is effective to divide the orientation direction of the liquid crystal molecules into a plurality of directions in one pixel (multi-domain orientation), and various types of technologies have been proposed for realizing the same. For example, Japanese Patent No. 4107978 (Patent Document 1) discloses technology (fringe electric field orientation control method) of generating fringe electric field s in two directions that differ by 180 degrees within the liquid crystal layer and controlling the orientation toward such directions by devising the electrode shape in a segment display-type liquid crystal display.
With the liquid crystal display of the foregoing conventional example, the upper and lower electrodes placed opposite each other need to be respectively provided with substantially rectangular openings, and the upper and lower electrodes need to be arranged so that the openings of the upper electrode and the openings of the lower electrode are alternately aligned in a planar view. Nevertheless, in order to realize the orientation stability of the liquid crystal layer in the liquid crystal display of the foregoing conventional example, since it is necessary to dispose the openings in cycles of approximately several tens of micrometers, there is a drawback in that high precision is required for the positioning of the upper and lower electrodes. Moreover, the aperture ratio of the display part will drop since numerous openings are provided, and there is concern that the transmissivity will drop during the bright display state.
In response to the foregoing problems, realization of the multi-domain alignment based on technology such as the photo alignment treatment method (for instance, refer to Japanese Patent No. 4373126) combined with mask exposure may be considered. Nevertheless, if these technologies are used, there is a drawback in that the alignment treatment will become complicated and prolong the processing time.
A specific mode of this invention aims to improve the display quality in a liquid crystal display.